Disposable connector for hemofiltration

ABSTRACT

The present invention refers to a disposable connector  20  suitable for engagement on the substitution port  180  of a hemo filtration machine  18.  The connector  20  comprises: a rigid main body  22  defining a duct  220;  and a soft element  24  fitted on an end of the main body  22.  In the connector  20  according to the invention, the soft element  24  comprises a membrane  240  occluding the duct  220  and performing a valve function; and a seal portion  242  radially expanding outward of the duct  220.

The invention concerns a disposable connector intended to be used formedical purposes; in particular a connector intended to be used duringhemofiltration and/or hemodiafiltration treatments.

Hemodialysis treatments require an extracorporeal blood circulation. Theblood circuit comprises an out-tube intended to supply blood from thepatient to the hemodialysis machine, where blood is passed through afilter in order to remove waste products. The blood circuit furthercomprises an in-tube intended to supply filtered blood from thehemodialysis machine back to the patient.

Most of the recent hemodialysis machines are designed to perform alsothe so called hemofiltration and/or hemodiafiltration treatments.Hemofiltration treatment implies the removal of some waste water fromthe blood and, accordingly, it needs also to compensate the removal bymeans of the addition of saline solution, i.e. the so calledsubstitution liquid. Where such treatment is combined with a traditionalhemodialysis, the so called hemodiafiltration treatment is obtained. Inthe following, for sake of simplicity, with the term “hemofiltration”reference will be made both to the actual hemofiltration and to thehemodiafiltration treatments.

Such recent hemodialysis machines further need a substitution lineintended to supply the substitution liquid in the blood flow directed tothe patient. According to some machines, for example the one disclosedin EP 2 059 279, the substitution line is obtained from the water system(see FIG. 1). In particular, water corning from the water system issubjected to an ultrafiltration treatment by the machine itself, then inthe ultrafiltered water salts are dissolved which are needed for makingit a physiological solution usable as a substitution liquid. Thus themachine comprises a port (shown in detail in FIGS. 2 and 3) intended tosupply the substitution liquid.

The substitution line of the disposable tubing set needs to be connectedto the substitution port of the machine by means of a disposableconnector. A disposable connector according to the prior art is shown inFIGS. 4 and 5. Such prior art connector, although widely used andappreciated, is not defect-free. It comprises four different components:a main body, a fixing thread, an o-ring seal, and a slotted membrane. Inaddition, the prior art connector comprises at least one removable capor, in the most complicated version shown in FIG. 4, two removable caps.The main body and the fixing thread are usually obtained frompolycarbonate or some other rigid material suitable for medical use. Theo-ring seal and the slotted membrane are usually obtained from siliconeor some other soft material suitable for medical use.

The assembly of the disposable connector of the known type requires thatthe membrane is inserted in its seat obtained along the duct of the mainbody, till it rests on the shoulder. Then also the fixing thread has tobe inserted along the same duct, till it contacts the membrane. The mainbody and the fixing thread are then joined together by means ofultrasound welding, so as to hold the silicone membrane in place. Theassembly of the known connector is then finished by slipping the o-ringseal along the main body to its seat and, in case, by putting on the twocaps.

As can be easily appreciated by the skilled person, the prior artconnector is quite complex and relatively expensive. The relatively highnumber of pieces, with respect to the overall dimensions of theconnector, requires a time-consuming assembly. Moreover, the ultrasoundwelding step requires both dedicated equipments and qualified personnel.

The aim of the present invention is therefore to at least partiallysolve the drawbacks highlighted in relation to known connectors forhemofiltration treatments.

A task of the present invention is to provide a disposable connectorhaving a simple structure, i.e. made of fewer components with respect tothe known one.

Another task of the present invention is to reduce the production andassembly costs of the disposable connector.

The aim and the tasks indicated above are accomplished by a disposableconnector according to claim 1.

The characteristics and the further advantages of the invention shallbecome clear from the following description of some embodiments, givenfor indicating and not limiting purposes with reference to the attacheddrawings, in which:

FIG. 1 schematically represents a hemofiltration machine and the relatedextracorporeal circuit used in a hemofiltration treatment of a patient'sblood;

FIG. 2 schematically represents a lateral cross section of thesubstitution port of the hemofiltration machine in FIG. 1;

FIG. 3 schematically represents the port of FIG. 2 in a differentconfiguration;

FIG. 4 schematically represents a cross section of a connector accordingto the prior art in a disconnected configuration;

FIG. 5 schematically represents a cross section of the connector of FIG.4 connected to the hemofiltration machine;

FIG. 6 schematically represents a cross section of a connector accordingto the invention in a disconnected configuration;

FIG. 7 schematically represents a cross section of the connector of FIG.6 connected to the hemofiltration machine;

FIG. 8 represents an exploded lateral view of the connector of FIG. 4;

FIG. 9 represents an exploded lateral view of the connector of FIG. 6;

FIGS. 10 and 11 schematically represent two views of a detail of theconnector according to the invention;

FIG. 12 schematically represents a cross section of a connectoraccording to a different embodiment of the invention;

FIG. 13 schematically represents a cross section of a connectoraccording to a different embodiment of the invention.

Referring to the enclosed figures, the reference 20 indicates adisposable connector suitable for engagement on the substitution port180 of a hemofiltration machine 18. The connector 20 comprises: a rigidmain body 22 defining a duct 220; and a soft element 24 fitted on an endof the main body 22. In the connector 20 according to the invention, thesoft element 24 comprises a membrane 240 occluding the duct 220 andperforming a valve function; and a seal portion 242 radially expandingoutward of the duct 220.

In the attached figures, same references are used for elements whichhave same or similar functions, both in the connector according to theinvention and in the one according to the prior art.

The main body 22 is preferably obtained from polycarbonate (PC),acrylonitrile-butadiene-styrene (ABS), unplasticized polyvinyl chloride(uPVC) or some other rigid material suitable for medical use. The softelement 24 is preferably obtained from silicone, thermoplastic elastomer(TPE) or some other soft material suitable for medical use.

According to the embodiments shown in the attached FIGS. 6, 7, 9 and 12,the connector 20 according to the invention is, as a whole, L-shaped.Specifically, duct 220 defined by the main body 22 is L-shaped, having amain axis X and a secondary axis Y, see in particular FIG. 6.Conversely, according to the embodiment shown in the attached FIG. 13,the connector 20 according to the invention has a straight development.Specifically, duct 220 defined by the main body 22 has a straightdevelopment, having one axis X only. In the following descriptionreference will be made principally to axis X. Consequently, except incase of explicit contrary indication, the term “axial” refers to thedirection of a straight line parallel to axis X, the term “radial”refers to the direction of a half-line having its origin on axis X andperpendicular thereto, the term “circumferential” refers to thedirection of a circumference having its centre on axis X and laying on aplane perpendicular thereto.

As can be noticed in FIGS. 2 and 3, the port 180 of the machine 18comprises an inner cone 184 and a coaxial outer sleeve 182. The innercone 184 defines a supply channel for the substitution liquid, while theouter sleeve 182 defines a protected interspace 188 around the innercone 184. The outer sleeve 182 further defines a drain channel 186 whichis used during the preparatory step for the hemofiltration treatment.Such step is schematically shown in FIG. 3 where the port 18 is closedby a proper plug. In such condition the substitution liquid coming fromthe machine 18 is forced to circulate between the outer wall of theinner cone 184 and the inner wall of the outer sleeve 182, and then toflow out through the drain channel 186. Such circulation allows anaccurate washing of the port 18, so as to assure hygiene of theconnection.

According to some embodiments of the disposable connector 20, themembrane 240 is suitable for alternatively assuming a closedconfiguration or an open configuration. In particular, membrane 240preferably assumes the closed configuration in a spontaneous manner, orat rest, i.e. in absence of any force directly acting upon it. See inthis regard FIG. 6 wherein connector 20 is shown isolated, disengagedfrom the machine 18.

Conversely, membrane 240 assumes the open configuration after engagementof the connector 20 on the machine 18, in particular because of thespecific conformation of the port 180 on which connector 20 is engaged.See in this regard FIG. 7 wherein connector 20 is shown engaged withport 180; it can be noticed that the inner cone 184 pushes the membrane240, forcing it to the open configuration. In such condition duct 220 ofconnector 20 becomes an extension of the supply channel defined by theinner cone 184. Moreover, in the open configuration, the membrane 240adheres on the outer wall of the inner cone 184, thus sealing the supplychannel from the interspace 188. A successive disengagement of theconnector 20 from the port 180, removing all the forces acting on themembrane 240, entails that the latter spontaneously assumes back itsclosed configuration, thus closing duct 220.

According to some embodiments of the invention, e.g. the one shown inFIGS. 6, 7, 9 and 13, the membrane 240 comprises a simple diametricalslot 241. According to other embodiments of the invention, e.g. the oneshown in FIGS. 10, 11 and 12, the membrane 240 comprises a Y-shaped slot241, i.e. a slot formed of three cuts extending radially from the centerof the membrane and spaced by 120° one from the other.

As disclosed above, the soft element 24 comprises also a seal portion242, intended to co-operate with the port 180 of the machine 18. Inparticular, the seal portion 242 is intended to make contact with theinner wall of the outer sleeve 182 so as to seal the interspace 188 fromthe outer environment. Engagement between connector 20 and port 180 ofthe machine 18 entails a slight interference between the seal portion242 and the inner wall of the outer sleeve 182. As can be noticed inFIGS. 9 and 11, wherein the seal portion 242 is free from any contact,the seal portion 242 radially extends outward and has a substantiallysemicircular cross section. On the contrary in FIG. 7, wherein the sealportion 242 is constricted by the inner wall of the outer sleeve 182,the seal portion 242 has a smaller radial extension and a squashed crosssection.

According to the embodiments shown in the attached figures, see inparticular FIG. 9, the main body 22 comprises an undercut 224 and anaxial shoulder 226 which radially extends outward. The undercut 224 isplaced near the end of the main body 22 upon which the soft element 24is fitted. Complementarily, the soft element 24 comprises a radial step244 which protrudes inward. When the soft element 24 is forcedly fittedon the end of the main body 22, the axial end 246 of the soft element 24contacts the shoulder 226 and the radial step 244 engages the undercut224. In such a manner a shape coupling is established between the softelement 24 and the main body 22.

The shape coupling assures that the connector 20 remains firmlyassembled during its use. According to some embodiments, such couplingis further strengthened by the specific shape of the soft element 24, orby the finish of the contact surfaces, or by both of them.

In particular, the coupling can be strengthened by the reciprocalpositions of the radial step 244 and of the seal portion 242 withrespect to the axial end 246. As can be noticed in FIG. 11, the distanceD between the radial step 244 and the axial end 246 is longer than orequal to the distance d between the seal portion 242 and the axial end246. When the connector 20 is engaged on the port 180, the specificrelationship between D and d allows to exploit the radial pressureexerted by the outer sleeve 182 on the seal portion 242 in order toprevent the radial step 244 from any possible disengagement from theundercut 224 due to its deformation.

The coupling between the main body 22 and the soft element 24 can alsobe strengthened by the finish of the respective surfaces which contacteach other. In particular, a very smooth surface finish entails a strongadhesion between the two surfaces. Accordingly, the contact zone 228 ofthe main body 22 (see FIG. 9) and the contact zone 248 of the softelement 24 (see FIG. 11) have very smooth surfaces, i.e. polished orlapped surfaces. As the skilled person will appreciate, since both themain body 22 and the soft element 24 are made of plastic materials,polishing and/or lapping treatments are actually carried out on therespective areas of the moulds, rather than on each single plasticpiece.

According to some embodiments, connector 20 further comprises one or twocaps referenced to with 26 and 28 respectively. Such caps, which aresuitable for plugging the ends of the duct 220, are intended to beremoved before use. FIG. 6 shows the connector 20 with both caps 26 and28. FIG. 7 shows the same connector 20 of FIG. 6 engaged on the port ISOand still having its cap 28 on. FIG. 12 shows a different embodiment ofthe connector 20 wherein only cap 26 is provided. Accordingly the otherend of duct 220 is open and, in particular, is suitable for receiving adelivery tube to be glued therein.

In view of the above description, the skilled person will easilyappreciate that the present invention overcomes most of the drawbackspointed out with respect to the prior art. In particular, the presentinvention provides a disposable connector having a simple structure,i.e. a disposable connector made of fewer components with respect to theknown one. This can be further appreciated by comparison of FIG. 9,showing an exploded view of the connector according to the invention,with FIG. 8, showing an exploded view of the connector according to theprior art. Accordingly, the present invention reduces the production andassembly costs of the disposable connector, as a matter of fact,assembly of the connector according to the invention simply requires tofit the soft element 24 on the main body 22.

The person skilled in the art can bring modifications and/orreplacements of described element with equivalent elements to theembodiments of the connector according to the invention described above,in order to satisfy specific requirements, without for this reasondeparting from the scope of the attached claims.

1. Connector (20) suitable for engagement on a substitution port (180)of a machine (18) for carrying out a hemofiltration or ahemodiafiltration treatment of a patient's blood, the connector (20)comprising: a rigid main body (22) defining a duct (220); and a softelement (24) fitted on an end of the main body (22); wherein said softelement (24) comprises a membrane (240) occluding the duct (220) andperforming a valve function; and a seal portion (242) radially expandingoutward of the duct (220).
 2. Connector (20) according to claim 1,characterized by being, as a whole, L-shaped and wherein the duct (220)defined by the main body (22) is also L-shaped.
 3. Connector (20)according to claim 1, wherein the substitution port (180) of the machine(18) comprises an inner cone (184) defining a supply channel for thesubstitution liquid, and a coaxial outer sleeve (182) defining aprotected interspace (188) around the inner cone (184).
 4. Connector(20) according to claim 1, wherein the membrane (240) is suitable foralternatively assuming a closed configuration or an open configuration.5. Connector (20) according to claim 4, wherein the membrane (240)assumes the closed configuration at rest, i.e. in absence of any forcedirectly acting upon it.
 6. Connector (20) according to claim 4, whereinthe membrane (240) assumes the open configuration after engagement ofthe connector (20) on the port (180), due to the inner cone (184)forcing it to the open configuration.
 7. Connector (20) according toclaim 1, wherein, in the open configuration, the membrane (240) adhereson the outer wall of the inner cone (184), thus sealing the duct (220)from the interspace (188).
 8. Connector (20) according to claim 1,wherein the membrane (240) comprises a diametrical slot (241). 9.Connector (20) according to claim 1, wherein the membrane (240)comprises a Y-shaped slot (241).
 10. Connector (20) according to claim1, wherein the seal portion (242) is intended to make contact with theinner wall of the outer sleeve (182) of the port (180) so as to seal theinterspace (188) from the outer environment.
 11. Connector (20)according to claim 1, wherein: the main body (22) comprises an undercut(224) near the end and an axial shoulder (226) radially extendingoutward; the soft element (24) comprises an axial end and a radial step(244) protruding inward; and when the soft element (24) is forcedlyfitted on the end of the main body (22), the axial end (246) of the softelement (24) contacts the shoulder (226) and the radial step (244)engages the undercut (224), thus a shape coupling is established betweenthe soft element (24) and the main body (22).
 12. Connector (20)according to claim 11, wherein in the soft element (24) the distance Dbetween the radial step (244) and the axial end (246) is longer than orequal to the distance d between the seal portion (242) and the axial end(246).
 13. Connector (20) according to claim 1, wherein the contact zone(228) of the main body (22) and the contact zone (248) of the softelement (24) have polished or lapped surfaces.
 14. Connector (20)according to claim 1, further comprising two caps (26, 28) suitable forplugging the ends of the duct (220) and intended to be removed beforeuse.
 15. Connector (20) according to claim 1, further comprising a cap(26) suitable for plugging an end of the duct (220) and intended to beremoved before use; and wherein the other end of duct (220) is open andsuitable for receiving a delivery tube to be glued therein.
 16. Assemblycomprising a connector (20) according to claim 1 engaged on asubstitution port (180) of a machine (18) for carrying out ahemofiltration or a hemodiafiltration treatment of a patient's blood.